Shock absorber



June 22, 1948. GRUSS snocx ABSORBER Filed March is, 1944 I I f 4 2Sheets-Sheet 2 IN V EN TOR.

L UC/E/V 1136mm:

aienied June 22, 1948 Ul'lED STATES PATENT orrlca SHOCK ABSORBER LucienR. Gross, Middletown, Ohio Application March 15, 1944, SerialNo..526,498

9 Claims. 1

This invention relates to shock absorbers for use between two relativelymovable members, such for example in connection with the landing gear ofaircraft, or the spring suspension of any motor vehicle. The inventionconstitutes an improvement on the structure shown in my copendingapplication. Serial No. 503,324, filed September 22, 19-13.

As applied to aircraft work, my copending application briefly embodiestwo telescopically movable members, each of which is mounted on one ofthe relatively movable parts, and one of which has a pin-like ram thatoperates against fluid under pressure in a cylinder of the other. Theshock incident to the landing is absorbed by the restricted flow offluid past the plunger as it moves progressively into the cylinder.

The present invention embodies an improvement over the priorconstruction in that it utilizes a floating ram, one end of whichoperates against fluid under pressure in a cylinder within one of thetelescopic members, and the other end of which operates against fluidunder pressure in a cylinder within the other telescopic member. Thisimproves the cushioning effect, strengthens the bearing construction andreduces the overall length required for the shock absorber.

A further object of the present invention is to simplify theconstruction and reduce the possibility of leakage of the shockabsorbing liquid.

Referring now to the drawings, Fig. 1 illustrates a vertical sectiontaken longitudinally through a shock absorber embodying the presentinvention and showing the position of the parts when the airplane (inthe case of aircraft) is oil the ground; Fig. 2 is a section similar toFig. 1, but showing the position of the parts when the airplane is onthe ground and when the shock absorber parts have reached theapproximate limit of their travel of their movement toward each other;Fig. 3 is a section through a portion of the operating parts,illustrating them on a wing and a member I l which may be attached inthe usual way to a wheel supporting bracket 1. Such members aretelescopically mounted with respect to each other and each has a.cylinder 9 and 9 therein respectively, shown as preferably being anaxial alignment, and as having a floating piston or ram operatingagainst a liquid and air cushion in each cylinder. Preferably, a pistonl2 operates in the cylinder 8 and has a fluid tight seal at itsperipheral portion with the wall of the cylinder and has a. rod II whichextends into the cylinder 9 and operates as a ram therein. For thispurpose, the rod is smaller in diameter than the bore of the cylinder 9so as to drive liquid in the cylinder out of it as the ram movesdownwardly therein. Such action takes place when the members move fromthe position shown in Fig. 1 to that shown in Fig. 2. The members arekept in alignment by means of links l and 5 which are respectivelyconnected to the members at I and 2, and are pivotally connectedtogether vat 3.

scale larger than that shown in either Fig. 1

or 2, and Fig. 4 is a section taken on a plane indicated by the line 4-4in Fig. 2, and .Figs. 5 and 6 are side and end views respectivelyshowing the device in elevation.

The invention as aforesaid is adapted for use between any two relativelymovable-parts, such for example, as the wing and landing wheel supportrespectively of an airplane, or the chassis frame and axle housing of amotor vehicle. In the case of an airplane, my invention includes amember I! which may be pivotally attached in the customary way throughthe band 6 to the The member I0 is enclosed at the upper end by a head Iand at the bottom by a cap i5, and is provided intermediately with apartition l6 which has an aperture through which the rod it extends. Thepartition divides the member into the cylinder 8 and a chamber i8 andhas a fluid tight seal with the walls of the cylinder and the wall ofthe piston rod respectively. The cylinder 8 above the piston i0 ispartially filled with a liquid, such as oil, and has a partition 25therein adjacent the upper portion thereof, which has a permanently openrestricted passageway 26 extending therethrough, together with a largeropening 21 in which a spring pressed valve 29 is positioned. The valveis normally urged to closing position in a downward direction. The spaceabove the oil is filled with air under pressure, that may be suppliedinitially through a valve 30 sufllcient to keep the piston I2 away fromthe partition l6 when the plane is standing on the ground. Sucharrangement enables the piston i2 as it moves upwardly in the cylinder 8to work against the liquid and gas under pressure therein, the valve 28operating to permit the fluid to move rapidly therethrough in an upwarddirection, but to cause it to move at a more restricted rate in theopposite direction solely through the opening 26. This cushions therebound and avoids an objectionable jerk on the wings of the airplane.

The member II, which as aforesaid is attached to the lower part to whichthis structure is applied, has a bearing against a cylindrical wall 35of the chamber l8 and for this purpose the upper end of the member H isenlarged in diameter to provide a head 38 as is shown in Fig. 3. Thereduced portion of the member H beneath the head, as shown at 31 in Fig.3, provides clearance between the member and the wall 35 so that anyliquid which may seep past the head 39 is forced backwardly into thechamber l8 through a passageway 38 and the valve 39 in the head,whenever the members are extended to the position of Fig. 1. Thus, thestructure is hydraulically sealed at all times.

The cylinder 9 has therein a shock absorbing liquid which is forcedupwardly and into the chamber l8 as the ram i3 descends within thecylinder, and flows backwardly into the cylinder as the ram is withdrawntherefrom. There is interposed between the cylinder and chamber a devicefor effecting a differential rate of flow of liquid therebetween as theram ascends and descends, and such device may take the form of afloating valve 40 which is illustrated as an annulus that embraces theram and is movable in a direction axially thereof within a recess 4| inthe head 36. Such valve has a clearance with the wall of the ram so asto permit a restricted flow of liquid from the cylinder 9 into thechamber l9 during the compression stroke of the ram l3, during whichtime the valve is forced upwardly against the seat which comprises thetop wall of the recess ll. however, the valve drops downwardly to theseat which forms the bottom wall of the recess ll, during which time theliquid may flow at an increased rate from the chamber l9 into thecylinder 9 through spaced passageways l! in the side bottom portion ofthe valve.

The present invention is well adapted for preventing the seepage of oilor other liquid used as a shock absorbing medium in that any liquidwhich seeps past the head 36 is forced upwardly into the chamber l8through the valve 39 as the members Ill and II move away from eachother, and in that any liquid which seeps past the piston I2 is forcedupwardly into the cylinder 9 through a valve 45 which is shown in Fig. 4as being located in a passageway within the piston l2. The 011 levels inthe various chambers are indicated by the dot and dash lines extendingacross Figures 1 and 2.

The present invention retains the feature of automatic pumping of airinto the cylinder above the piston l2 as the airplane skips along theground during a take-off operation, because air may enter the chamber l8through a breather pipe 50 which has the customary check valve(Bl-shown) therein and air may pass from the chamber it into thecylinder 8 beneath the piston l2 through the passageway in the ram [3when the upper end 52 of the passageway is above the partition 16, whilethe lower end 53 thereof is below the partition l9. This equalizes anypressure differential between the chambers 9 and I8, and then on thedownstroke of the piston l2, any air that is trapped in the cylinder 8below the piston, and after the upper end 52 of the passageway clearsthepartition I8, is forced upwardly into the space above the piston I!through the valve 45. Thus repeated reciprocations of the piston buildsup an air pressure above the piston to an amount that is determined by apressure relief valve 54 which may be set to keep the pressure fromexceeding a predetermined maximum amount.

Assuming that a structure embodying my in- On the reverse stroke of theram,

vention has the telescopic members attached respectively to the upperand lower relatively movable parts of the article which requires a shockabsorbing medium, and assuming further that there is an adequatequantity of liquid in the cylinder 9 to occupy the chamber 18 when theparts are in retracted position as shown in Fig. 2, and that there issufllclent liquid above the piston l2 and air pressure above that tosupport the piston in the position shown in Fig. 2 in retractedposition, then as the relatively movable parts move away from each other(consequent upon the airplane leaving the ground), the piston rod or ramI3 is moved upwardly in the cylinder 9 until the head 36 on the memberll strikes the cap ii on the member l0. At such time the piston l2 willhave moveddownwardly to the position shown in Fig. 1. Assuming then thatthe plane is skipped along the ground, then as the wheels strike theground, the member ll moves toward the member Ill, whereby the piston l2compresses the air above it in cylinder 8 and the ram l3 forces theliquid in the cylinder 9 upwardly into the chamber l8, thereby making aconjoint liquid and gaseous cushioning'means which operates in asatisfactory manner to afford an extended length of travel of the shockabsorbing members without permitting a sudden impact of an unyieldingnature between any two relatively movable members. The skippingoperation may be continued until the pressure above the piston I2 isbuilt up, as aforesaid, suflicient to absorb the landing shock.

An important advantage of the present invention is the fact that thevarious parts may be readily manufactured and assembled, and that theycoact to provide an effective and satisfactory cushioning medium, whileat the same time retaining the advantage of automatically building upthe pressure within the structure consequent upon a skipping action ofthe airplane along the ground. The invention additionally isadvantageous in that the liquid therein cannot escape therefrom duringthe operation of the device.

I claim: v 1. A shockabsorbing device for use betwee two relativelymovable parts, comprising two telescopically movable members, eachmounted 'on one of the relatively movable parts, one of the membershaving a partition therein dividing it into a cylinder and a chamber,the other member having a cylinder therein having one end thereof opento the chamber in the first-mentioned member, a piston operating in thecylinder of the first mentioned member and having a shank extendingthrough the partition and into the cylinder in the other of said membersand operating as a ram therein, each of said cylinders having fluidtherein against which the piston and ram respectively are adapted tooperate, said partition operating to prevent the passage of fluidbetween the cylinders, the piston forming a peripheral seal with thewalls of its associated cylinder and the ram having a clearance with thewalls of its associated cylinder.

2. A shock absorber for use between two relatively movable parts,comprising two telescopically movable members, each mounted on one ofthe relatively movable parts, one of said members having a partitiondividing it into a cylinder and a chamber, the other of said membershaving a cylinder closed at one end but open at the other into saidchamber, the first-mentioned cylinder having a partition and having afluid passageway therethrough providing communication from one side tothe other thereof, and a floating ram having a portion thereof disposedin each cylinder and operating against fluid pressure therein.

I3. A shock absorber for use between two relatively movable parts,comprising two telescopically movable members, each mounted on one ofthe relatively movable parts, one of said members having a partitiontherein dividing it into a cylinder and a chamber, and the other of saidmembers having a cylinder therein closed at one end and opening at theother end into said chamber, each of said cylinders being partiallyfilled with liquid, a piston operating in the first-mentioned cylinderand having its peripheral portion sealed against the passage of liquidfrom one side thereof to the other, said piston having a rod projectingthrough the partition and operating as a ram in the other of saidcylinders, said ram having a clearance between its peripheral surfaceand the walls of the associated cylinder, whereby, on descent of theram, liquid in said cylinder is forced axially thereof into said clear-7 ance space, out of the cylinder, and into said chamber, and whereby,upon ascent of the piston, liquid in the first-named cylinder is forcedahead of the piston, said partition operating to prevent the transfer ofliquid from one cylinder to the other during use.

4. A shock absorbing device for use between two relatively movableparts, comprising two members adapted to be attached to the respectiveparts and telescopically movable with respect to each other, one of saidmembers having a partition therein dividing it into a cylinder and achamber, and the other member having a cylinder therein opening intosaid chamber. means providlng communication between the atmosphere andthe chamber whenever the pressure within the chamber drops below that ofthe atmosphere, a piston operating in one of the cylinders and having arod extending through said partition and chamber and operating in theother of said cylinders, said rod having a longitudinally extendingpassageway therein opening at spaced intervals onto the surface thereof,the distance between said openings being greater than the thickness ofsaid partition, whereby the rod during reciprocation thereof providescommunication between the chamber and cylinder on one side of saidpiston, and said piston having a check valve therein operating to permitthe flow of air from the underside thereof to the upper side thereof,whenever the upper opening in said passageway is beneath said partition,whereby the air pressure on top of the piston is automatically increasedas the piston is reciprocated, and means in communication with thecylinder above said piston to limit the degree of pressure attainabletherein.

5. A shock absorbing device for use between two relatively movable partscomprising two telescopic members, one of said members constituting acylinder, the other member having a chamber into which the cylindertelescopes and carrying a second cylinder separated by a partition fromsaid chamber, a piston in the second cylinder, a rod connected to saidpiston and slidable through said partition and extending as a ram intothe first cylinder, means for controlling communication from thechamberto the space above the partition and means to control the rate of flowfrom the ram cylinder to said chamber restricting it more in theoutgoing than the incoming direction.

6. A shock absorbing device for use between two relatively movable partscomprising two telescopic members, one of said members constituting acylinder, the other member having a cham-- ber into which the cylindertelescopes and carrying a second cylinder separated by a partition fromsaid chamber, a piston in the second cylinder, a rod connected to saidpiston and slidable through said partition and extending as a ram intothe first cylinder, means operated by the movement of the piston forcontrolling communication from the chamber to the space between thepartition and piston, and a floating ring encircling the ram and adaptedto control the rate of flow from the ram cylinder to said chamber.

7. A shock absorbing device for use between two relatively movable partscomprising two telescopic members, one of the members having a cylinderand the other member having a chamber and carrying a second cylinderseparated by a partition from said chamber, a piston in the secondcylinder, a rod connected to said piston and slidable through saidpartition and operating a ram on the first cylinder, there being apassageway through the piston rod which passageway in one position ofthe rod extends from said chamber to the space between said piston andpartition, and a valve carried by the piston for allowing the passage ofair from beneath the piston into the space above the piston.

8. A shock absorbing device for use between two relatively movable partscomprising a cylinder and a second cylinder telescopically movable withreference to the first cylinder, a piston operating in the firstcylinder and having an extension thereon operating in the secondcylinder, means disposed adjacent the end of the first cylinder forembracing the second cylinder and sealing it against the passage offluid therebetween. the second cylinder carrying a seal adapted to bearagainst the first cylinder, there being clearance space between saidcylinders below the last-mentioned seal, a passageway in said secondcylinder extending from the space above that cylinder to said clearancespace, a valve in said passageway adapted to permit air to pass fromsaid clearance space to the space above said second cylinder consequentupon the extension of I such cylinders with respect to each other, apassageway in the wall of said first-named cylinder and a valve in thelast-mentioned passageway operating to permit the passage of air fromthe exterior of the device to said clearance space consequent upon thecollapsing of said cylinders.

9. A shock absorber for attachment to the landing gear of an airplaneand adapted to pump air into a cylinder as the airplane skips along theground during a take-off, comprising said cylinder and a head thereon, asecond cylinder, a third cylinder rigid with the first-named cylinderand in which the second-named cylinder reciprocates, a piston in thefirst cylinder, a rod connected to said piston and extending throughsaid head and through a chamber provided by said third cylinder into thesecond cylinder, a passageway from the exterior into said chamberbeneath said head, a passageway in the rod adapted to establishcommunication between said chamber and the space in the first cylinderbetween the head and the piston, and a valve controlled passageway inthe piston allowing the air between the piston and head to pass throughthe piston into the space in the first cylinder above the piston as thepiston moves toward the head, whereby repeated reciprocatlons of theNumber piston build up air pressure above the piston. 1,841,287 LUCIENR. GRUSS. 1,918,697 1,969,508 REFERENCES CITED 5 2,186,011 The followingreferences are of record in the 2343,16 file -01 this patent:

UNITED STATES PATENTS Number Number Name Date 563,913 1,055,734 FunkMar. 11, 1913 782,123 1,819,414 Gruss Aug. 18, 1931 852,704

8 Name Date Gruss Jan. 12, 1932 Gruss July 18, 1933 Gruss Aug. 7, 1934DePort Jan. 9,1940 Thornhlll May 2, 1944 FOREIGN PATENTS Country DateFrance Oct. 6, 1923 France Mar. 11, 1935 France Nov. 9, 1939

